Food intolerance or allergy? Is there anything pet-owners can do to avoid this pain?

Updated: Jul 13

Food allergies are not as common as you think. Also, food allergy means something different than food intolerance.

Is it a lot to learn at once? Trust me. I will keep it short and compressed.



Food intolerance comes as a result of poor digestion of carbohydrates, for example, lactose intolerance. Only in rare cases dog can be allergic to the protein in milk. Yet, for lactose intolerant dogs dairy products can present a real problem. That’s because of a dog’s reaction to lactose.

The good news is that food intolerance can be directly related to dosage - the higher the lactose content, the greater the likely response. Look at the table below to check how some dairy products contain only a minimal amount of lactose per serving. Your dog can still enjoy some dairy products in small amounts.




Food allergies occur when the immune system misidentifies a protein from food as an invader and over-respond to it. Proteins are present in most pet food. They are not only in meat but also in grains and vegetables. Any one of these proteins has the potential to cause a food allergy. The more the pet is exposed to the allergen, the more severe the reaction will become.

Dogs can be allergic to nearly any specific food ingredient. The bad news here is that if your dog is allergic to one, he will very likely be allergic to other ingredients too.

A list of products to especially watch out for is presented in the table below.


The most often recognised food allergens in dogs and cats are chicken, beef, dairy, and egg (and fish for cats). However, wheat is also very high on the list. This fact has encouraged many pet food manufacturers to increase their Grain-Free product lines.


A Series of research and investigations are conducted currently after veterinarians across the country spotted a correlation between feeding dogs a BEG diet (Boutique, Exotic and Grain-free food) and developing the deadly heart disease called dilated cardiomyopathy (DCM). The suspicion is that dogs on the BEG diet are being diagnosed with the disease at a higher rate. Typically BEG diets include ingredients like kangaroo, duck, buffalo, salmon, lamb, bison, venison, lentils, peas, fava beans, tapioca or barley as the main ingredient.

TEDDY posing in a field of gold grains - @Paws-to-tours, Wiltshire.

Picture thanks to Emma Lovell

Oh, BDW, this is a good topic for the next article… but now back to allergy


Food allergy is only one of the possible causes of your pet’s itchy skin, ear infections, or diarrhoea. Many causes may actually have nothing to do with the food. The most common cause of itching, skin infections, and ear infections in dogs and cats are fleas and environmental allergies such as dust mites, pollen, and grasses. However, they all have similar symptoms: Chronic ear inflammation, Itching, Paw biting, Poor coat quality, Obsessive licking, Skin rash, Hives, Itching, Nausea, Chronic diarrhoea, Itchy rear end, Chronic gas, and Vomiting.

Dog behavioural issues triged from Food Allergies includes:

  • Frequent scratching of self on furniture, owner's legs, etc.

  • Restlessness

  • Frequent shaking ears or scratching ears

  • Biting at paws, rear end, and/or tail

  • Withdrawal or reduced interest in playtime

  • Anorexia, or disinterest in or refusal of food

As soon as you notice any of the symptoms or behaviours above make an appointment with your vet. You know your dog best. If they don’t have the symptoms listed above but you are still concerned it’s always best to consult with your vet.




You probably wonder now, how to test your pet for the possible allergies?

Therefore, the best method for diagnosing food allergies in pets is the dietary elimination trial. It means feeding your pet a diet (purchased through a veterinarian or carefully made at home) that contains limited ingredients, and that your pet has never been fed before. You then feed this diet as the only food for your pet for at least a month and observe him. If symptoms disappear during the trial, to confirm a food allergy, your pet has to go back to the old diet again. You then go back to the test diet until things get better again.


This is a long-lasting process as you have to go one ingredient from the old diet at a time until you identify the specific foods that trigger the problem.

The second part of this process, “re-challenge” is very important here. Without going back to the old diet, we can’t find out if the improvement was coincidence or the diet that actually helped the pet!


Quite commonly pet owners assume it was the diet that caused the improvement in their pet’s allergies when actually it is seasonal allergens – such as certain pollens are much reduced in the changing season.



To conclude, there is nothing pet-owners can do to prevent a food allergy or any other allergy in their pet’s. Feeding a diet with duck, lamb, or venison doesn’t prevent food allergies, it just makes it likely that if your pet develops one, it will be to that protein instead of something more common like pork or chicken.


Only spotting the signs early will help you get your pet back to normal and minimise their pain, so please, please, please… keep an eye on your furry friend and react quickly!

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